Broiler for gas range



J. C. WEISS BROILER FOR GAS RANGE Sheet Jan. 21, 1969 Filed Sept. 8, 1967 a llllllllllllllllllllllllllllllllllllllllll l| J. C. WEISS BROILER FOR GAS RANGE Jan. 21, 1969 e 5 NP? mm M. Q 2 mam t 31% M m WW mm s \N W k 5W \w wflllu w w V o h m Mr m. \w n w .mw F \IIQ Jan. 21, 1969 J. c. WEISS 3,422,810

BROILER FOR GAS RANGE Filed Sept. 8, 1967 7 Sheet 3 of 5 United States Patent Patented Jan. 21, 1969 7 Claims ABSTRACT OF THE DISCLOSURE A broiler for a gas range utilizing an extensive layer of perforated incandescent material and having improved means for initiating combustion as well as an improved mounting and air supply.

It is an object of the present invention to provide an improved broiler for a gas range which is distinguished by high thermal efficiency and which utilizes incandescence to produce high temperature radiation at a low fuel rate. It is another object of the invention to provide a broiler which employs incandescent burner elements which have the characteristic of burning without visible tongues of flame and in which the radiant energy is distributed over a broad spectrum from the long infrared rays, which penetrate deeply into the foodstuff, to the shorter rays which tend to act upon the surface. It is a related object to provide a gas broiler which is particularly suited for broiling and charring steak and other cuts of meat but which provides an even distribution of the heat over the broiling area without hot spots or regions of concentration. The degree of surface charring is however under the complete control of the user, being variable from a maximum charting effect with the foodstuff spaced closely to the burner to complete lack of surface charring as the spacing is progressively increased. Closer spacings are possible without sacrificing the evenness of heat distribution than is the case with conventional gas broilers employing downwardly extending tongues of flame.

It is another object of the present invention to provide an incandescent gas burner employing rare earth oxides having a large total area and a large cumulative port area but requiring only a low rate of flow of the gas-air mix per unit area and with a correspondingly low back pressure. It is a related object to provide, in an incandescent broiler burner of this type, an improved means for insuring positive ignition. It is a more specific object to provide means for augmenting the pressure and rate of flow of the gas over a localized region on the burner surface, with the pilot located opposite this localized region for initiating combustion which thereupon spreads over the entire burner area.

It is a more detailed object to provide a broiler burner having a novel supply of primary air which is uncontaminated by the products of combustion and which prevents the products of combustion of a burner located in a lower range compartment from passing through the radiant burner when it is inoperative.

Finally it is an object to provide a burner of the incandescent type having a novel gas-supplying and supporting arrangement which enables plugging of the burner into an air-gas receptacle in the rear wall of the oven, permitting the burner itself to be of simple construction, easily and quickly installed or removed, and keeping the interior of the oven or broiling space clean and uncluttered.

Other objects and advantages of the invention will become apparent upon reading the attached detailed description and upon reference to the drawings in which:

FIGURE 1 is a side elevation of an oven or broiling chamber in a range with the rear wall removed to reveal the broiler burner;

FIG. 2 is a front view corresponding to FIG. 1;

FIG. 3 is a vertical section taken longitudinally through the burner along the line 33 in FIG. 2;

FIG. 4 is an inner end section of the burner taken along the line 4-4 in FIG. 3;

FIG. 5 is a bottom view of the burner;

FIG. 6 is a perspective of a portion of the burner housing without the burner elements in place as viewed from the underside showing the auxiliary passageway for conducting gas-air mix to a localized region of the burner;

FIG. 7 is a fragmentary section taken through a typical burner element;

FIG. 8 is an exploded fragmentary perspective showing the clip used to clamp the burner in place.

While the invention has been described in connection with a preferred embodiment, it will be understood that I do not intend to be limited to the particular embodiment shown but intend, on the contrary, to cover the various alternative and equivalent constructions included within the spirit and scope of the appended claims.

Turning now to the drawings there is shown in FIG- URES 1 and 2 range structure 10 defining a broiler or oven compartment having a top wall 11, a bottom wall 12, a rear wall 13 and side walls 14, 15. A rack 16 capable of being supported on guides 17 secured tothe side walls serves to hold the foodstuff 18 as it is being broiled.

Arranged at the top of the broiling chamber is a broiler burner indicated generally at 20 having a conduit 21 which supplies air-gas mix. Gas is ejected from a jet 22 (see FIG. 3) having a supply line 23 which receives gas from a valve shown diagrammatically at 24. In carrying out the invention the gas jet 22 is mounted in the back portion of the range surrounded by a primary air chamber from which air is induced by the gas jet and which has a primary air intake which is spaced downwardly from the burner by a substantial amount in order to avoid contaminating the primary air with the products of combustion from the burner. Thus to the rear of, and surrounding, the gas jet 22 I provide an air chamber 30 having an annular outlet 31 concentric with the jet 22 and having an inlet 32. Secured over the inlet 32 is a baffle 35 of shallow rectangular or box shape having mounting flanges 36 and an open bottom edge 37 through which the air is admitted from the broiling compartment. The path of the air to the burner conduit is indicated by the arrow 38.

For the purpose of defining a venturi in the region of the jet for aspiration of the primary air, the conduit 21 includes a venturi insert 40 (see FIG. 3). The insert is flared at its outer end 41. For mating with and supporting the end of the conduit 21, a receptacle is provided surrounding the gas jet in the back wall of the oven. In the present instance the receptacle is in the form of a short nipple 42 providing a tapered annular seat 43. For the purpose of sealing the joint, a gasket 45 is provided between the seat 43 and the flare 41 of the venturi insert. The means for supporting the forward edge of the burner 20 and for maintaining the gasket 45 compressed to form a gas tight seal will be discussed at a later point.

In accordance with the present invention the broiler burner is formed of a hollow metallic housing providing a generally flat and extensive wall defining an air-gas plenum and with the wall being formed by a layer of incandescent rare earth oxide having a two-dimensional pattern of closely spaced perforations so that combustion occurs over the entire face of the oxide layer heating it to incandescence as a source of broiling heat free of any visible tongues of flame.

Thus referring to FIGS. 3-6 I provide a burner housing 50 which is of inverted pan shape having a top 51 and open bottom surface 52, a rear end wall 53 and a front end wall 54. The rear end wall 53 is perforated by, and serves to mount, the conduit 21. Integral with the side and end walls is a peripheral mounting flange 55.

Secured by the mounting flange is a burner element assembly 60 having a metal frame 61 and mounting a plurality of ceramic blocks 62 which are of square configuration and of which the face portion preferably consists of a rare earth oxide, or mixture of oxides, capable of incandescence when in close proximity to oxidation of a combustible gas. As shown in FIG. 5, the incandescent blocks 62 are stacked side by side separated by a thin layer of high temperature gasketing material 63, for example, asbestos paper. Each of the blocks 62 is provided with a two-dimensional pattern of through-openings 65. Formed on the surface of each of the blocks is a pattern of ridges 66 defining intervening valleys 67. As will be noted in FIG. 7 the rows of holes 65 alternately communicate with the ridges and valleys. Forming the surface in this way substantially increases the area of the active material and improves the combustion thereby to increase radiant efliciency. In a practical case each of the ceramic burner elements may measure approximately 1.75 by 1.50" with a thickness of 0.50". The com-municating openings 65 each have a diameter on the order of 0.03125" and are spaced center to center in each direction by 0.0625. The ridges 66 preferably have a width and height on the order of 0.0625", although the ridges may be omitted, if desired, without departing from the invention.

In accordance with one of the features of the present invention the incandescent blocks are arranged only about the periphery of the radiant burner face while the central portion thereof is covered by a metal panel which is impenvious to gas so that no combustion takes place in the central portion. This central panel, indicated at 70, is of rectangular shape, having an edge 71 which overlies the edges of the ceramic blocks. Secured to the inside surface of the panel 70 is a retaining member 72 of shallow pan shape having a peripheral flange 73, the panel and retainer being preferably spot welded together. The inner edge of each of the blocks is therefore snu ggly confined between the edge 71 of the panel and the flange 73 of the retainer. To provide central support for the block and panel assembly, idepending brackets 75 secured to the top wall of the housing (see FIG. 4) are provided. Blind rivets 76 extend through alined openings in the panel, (retainer and bracket, thereby rigidifying the face of the burner.

It will be apparent, then, that when air-gas mix is supplied to the plenum within the burner it will flow through the numerous openings 65 with combustion taking place over the face area of the blocks. Since there is no combustion at the central portion of the burner there is no build-up of temperature at the center so that heat is applied evenly over the entire area of the foodstuff. Preferably, and as shown, the central non-radiating portion has an area which is a major fraction of the area of the peripheral radiating portion.

In accordance with one of the important aspects of the present invention means are provided for augmenting the flow of air-gas mix to a localized region of the burner face to increase the rate of flow in such region to a level which insures that combustion will be initiated by a pilot placed adjacent thereto. I prefer to bring about this augmentation by means of a scoop or diverter placed in the path of the gas flowing through the conduit 21 and by providing a cooperating auxiliary passageway for conducting the air-gas mix to a small burner block area at the periphery of the burner assembly. Thus referring to FIG. 3, it will be noted that the air-gas conduit 21 terminates well within the housing, preferably at the center thereof, so that no portion of the burner is particularly farvore'd. In the path of movement of the air-gas mix exiting from the conduit is a diverter or scoop 80 which may be formed of a small piece of metal, angledas shown in FIG. 5, and spot welded or otherwise secured to the burner housing. Cooperating with the diverter, and defining an auxiliary passageway 81 is a channel 82 having mounting flanges 83 spot .welded in place. The passageway 81 terminates in an orifice 85 at the back side of a selected burner block 86.

Positioned at the front side of the burner block 86 is a pilot jet 90 having a thin flexible gas line 911 and a primary air supply tube 92. In order to avoid contamination of the primary air to the pilot, the supply tube 92 extends within and substantially to the lower edge of the baffle 35 previously described. The pilot flame 93 is positioned to play over the portion 85 of the block 86 through which gas is discharged at an augmented rate. Also in the vicinity of the pilot flame 93 is a sensor 94. The sensor and its associated control circuitry (not shown) is entirely conventional and is provided for the purpose of Idetecting the presence of a pilot flame, preventing flow of gas to the burner vin the absence of a flame in the interest of safety.

In order to further equalize the distribution of gas pressure within the plenum, the conduit is surrounded by a distribution box 95 which is spot welded to the top of the burner housing and which provides a series of escape openings 96, 97 along its sides. The distribution box is cut out as necessary to pass the air-gas mix which flows from the diverter 80 into the auxiliary passage 81.

Accordingly when the valve 24 is operated to turn on the gas, assuming the pilot is lit, gas flows from the main gas jet 22 into the venturi 40. By well known venturi action this induces a flow of primary air through the annular space 31 surrounding the jet, the air being intimately mixed with the gas during flow through the conduit. A portion of the air-gas mix exiting from the inner end of the conduit strikes the scoop 80 and is diverted thereby into the auxiliary passageway 1. This causes the pressure, and hence rate of flow, to 'be slightly higher in the pilot region 85 than it is over the remainder of the burner face. Thus the air-gas mix exiting in the region 85 is positively ignited by the pilot flame. Once ignition is initiated combustion spreads over the entire active burner surface. It is found that in the absence of the augmentation described above, and in view of the low back pressure existing in the plenum, lighting is difficult and unreliable, with the rising products of combustion of the pilot tending to drive the air-gas mix backwardly through the orifices in the adjacent burner block.

The pilot is preferably of the aerated type having a separate source of primary air, thereby minimizing the consumption of oxygen at the pilot flame and insuring that there is, in the region of lighting, suflicient secondary air to facilitate ignition and spread of combustion.

Once combustion has spread to all portions of the burner it is found that burning occurs evenly, immediately raising the temperature over all of the active surface to the incandescent level; Combustion takes place even at the region 85 without any obvious hot spot or visible tongues of flame in this area, notwithstanding augmentation of the flow.

In a practical broiler burner of the present design intended for domestic use; the burner may have a face area on the order of 9" by 14" with the central panel approximately 5 /2" by 11", leaving a total active incandescent area on the order of 66 square inches. Since the orifices in the incandescent blocks are numerous and closely spaced they provide total cumulative port area of 26.5 square inches. With all of this area available for the exiting'air-gas mix, the back pressure, at a heat rate of 18,000 B.t.u. per hour, is extremely low well below 1 (one) inch of water. Notwithstanding this low back pressure experience shows that combustion occurs reliably and with high efliciency over the entire active area and that the combustion is substantially proof against accidental blow-out by drafts, etc.

Since the incandescent temperatures of the burner blocks are below 2400" E, the blocks preferably consist of oxides of alumina, silica, calcium, or combinations thereof, rather than the more costly oxides of magnesium, thorium, or cerium, which are frequently employed at temperatures above 2400 F. The preferred oxides convert the energy of combustion to a wide spectrum of thermal radiation. Such radiation permits an even temperature to be achieved at the foodstuff which is substantially higher than that which can be achieved over the same area by an open flame at the same fuel rate. The present burner is thus particularly desirable where it is desired to sear or char meat, with the meat under such conditions being placed as close to the burner as may be desired. The searing and charring effect enhances the flavor while the longer rays penetrate deeply into the meat to insure that it is adequately done at the center in a minimum period of broiling time. Any spatter which strikes the burner under normal broiling conditions is immediately decomposed and vaporized at the high temperature at which combustion occurs. The central panel 70 and peripheral flange 55 acquire a sufficiently high temperature, on the order of 1050 to 1100 degrees F., so that they are also self-cleaning. Thus the burner not only operates smokelessly but is constantly self-cleaning and may be expected to last the entire life of the range in which it is installed.

In the event that it is desired to remove the burner for any purpose whatsoever this may be accomplished simply by loosening two clips along the opposite front edges of the burner, following which the burner may be pulled forwardly a short distance to disengage the nipple 42 at the back wall of the broiling chamber. Turning to FIG. 3, and as shown in detail in FIG. 8, the lateral flanges 55 of the burner housing are seated against rails 100 which run from front to back within the broiling chamber. Secured to each of the rails at the front of the broiler housing is a metal retaining clip 101 which is formed of a flat piece of metal bent into Z configuration having a supporting flange 102 and a mounting flange 103, with the mounting flange being secured to the fiat undersurface of the rail 100 by means of a screw 105. The screw 105 is threaded into the rail and engages an elongated hole 106 in the clip. Integrally formed at the front portion of the mounting flange 102 is an upwardly bent tab 107 which engages the front edge of the flange on the burner housing.

During installation, then, the burner housing is lifted into place with the inlet end of the conduit engaging the nipple receptacle 42 at the receptacle at the rear of the chamber. The clips 101 are then fastened in place. Prior to tightening the screws 105, the clips are pressed rearwardly, with the tabs 107 applying sufficient force to the burner housing in a rearward direction to insure compression of the sealing gasket 45 at the nipple.

The present burner construction not only improves the broiling process but due to the fact that the burner is characterized by an extensive flat undersurface the burner may be recessed in the top of the oven or broiling chamber thereby defining a smoothly continuous upper wall free of piping and avoiding the unsightly appearance of the conventional broiler burner. Moreover since the primary air passages to the main burner are integral with an concealed behind the rear wall of the chamber, such rear wall is also smoothly continuous except for the bafile 35 which is shallow construction and therefore does not substantially intrude upon the available space. Since the lower or inlet edge of the bafile 35 is well down from the broiler burner, the primary air which enters is fresh and uncontaminated by the products of combustion of the burner. This broiler burner air entry technique also prevents the products of combustion of any oven burner which may be located below the broiling cavity from passing through the broiler burner when inoperative. Suitable vents at the top of the range structure permit escape of the products of combustion from the broiler burner either into an external vent or into the room whichever is desired, the products in any event being clean and free of the smoke which is often associated with the broiling process.

It will be apparent to one skilled in the art that the present broiler burner is applicable to all domestic gas ranges whether of the free standing or the built-in type.

In the following claims the term incandescent is used as an adjective to denote a ceramic material capable of producing radiation in the visual and infra-red range when in the presence of gaseous combustion. A ceramic material includes any refractory which is capable of operating in the presence of combustion without substantial deterioration. The term lower portion of the chamber refers to any level substantially below the level of the burner.

I claim as my invention:

1. In a broiler burner for a gas range the combination comprising an extensive face formed of incandescent ceramic material having a two-dimensional pattern of closely spaced perforations, means defining a plenum chamber in back of the face in communication with the perforations, means defining a conduit for conducting airgas mix under slight pressure to the plenum chamber, means defining an auxiliary passage interconnecting the conduit and a localized region of the face for causing the air-gas mix to be supplied to said localized region at a slightly higher pressure than exists over the remainder of the face, and pilot means at said localized region of the face for initiating combustion of the exiting air-gas mix for lighting of the burner.

2. In a broiler burner for a gas range the combination comprising a hollow burner housing, one Wall of said housing being formed of incandescent ceramic material to form a heat-radiating face, said face having a twodimensional pattern of closely spaced perforations, means including a conduit connected to a source of air and gas under slight pressure and terminating in the housing for admi ting air-gas mix to the housing for distribution and escape thereof through the perforations, means defining an auxiliary passage interconnecting the conduit and a localized region of the face including a diverter for diverting air-gas mix through said auxiliary passage so that the air-gas mix is forced through the perforations at the localized area at a slightly greater pressure and hence at a higher rate than is effective over the other areas of the face, and pilot means at said localized region for initiating combustion of the exiting air-gas mix for lighting of the burner.

3. In a broiler burner for a gas range the combination comprising a fiat housing, a face on said housing formed of incandescent ceramic material having a two-dimensional pattern of closely spaced perforations, a tube extending into the housing parallel to the face thereof and having an inlet and an outlet, means for supplying airgas mix under slight pressure to the inlet, means defining an auxiliary passage extending from the outlet of the tube to a localized region of perforations located at one edge of the face, and a diverter in the path of the air-gas mix as it exits from the tube for diverting a portion of the exiting mix into the auxiliary passageway so that the air-gas mix is supplied to the perforations at the localized area at augmented pressure, and pilot means adjacent the localized region for initiating combustion of the air-gas mix over the face of the burner.

4. In a broiler burner for a gas range the combination comprising a hollow burner housing defining a generally flat and extensvie wall, means for supplying air-gas mix to the housing, said wall having a peripheral portion and a central metal panel, the peripheral portion being faced with an incandescent ceramic material having a twodimensionahpattern of closely spaced perforations for conducting air-gas mix from the housing through the per forations for combustion at the face thereof, the central panel being impervious to the flow of gas so that combustion takes place only about the peripheral portion of the burner for substantially even distribution of heat upon an extensive foodstuff arranged opposite the burner wall, the central metal panel having an area which is a major fraction of the area of the peripheral portion and contiguous to the peripheral portion so as to be heated therby when the burner is on.

5. In a broiler burner for a gas range the combination comprising a hollow burner housing of inverted pan shape having a generally fiat and extensive wall on its underside, said wall having a peripheral portion and a central panel, the peripheral portion being faced with incandescent ceramic material having a two-dimensional pattern of closely spaced perforations, the central panel being impervious to the flow of gas so that combustion takes place only about the peripheral portion of the burner, a conduit for admitting air-gas mix to the housing and terminating well within the housing, and a distribution box extending parallel to the conduit and surrounding the same, said distribution box having openings distributed therealong for even distribution of the gas-air mix to all portions of the housing, the central panel being contiguous to the peripheral portion so as to be heated thereby when the burner is on.

6. In a broiler burner for a gas range the combination comprising means defining a broiling chamber, a generally flat burner housing having an extensive downwardly facing wall, said wall being comprised of incandescent ceramic material to form a heat radiating face, said face having a two-dimensional pattern of closely spaced perforations, a conduit extending rearwardly from the housing, means defining a receptacle in the rear wall of the broiling chamber, supports for said housing for holding the housing in broiling position with the condit extending face when the burner housing is in broiling position in the receptacle, and a bafiie covering said opening and extending down to the lower portion of the chamber so that clean primary air is drawn from the lower portion of the chamber.

7. In a broiler burner for a gas range the combination comprising means defining a broiling chamber, a generally fiat burner housing having an extensive downwardly facing wall, said wall being comprised of incandescent ceramic material to form a heat radiating face, said face having a two-dimensional pattern of closely spaced perforations, a conduit extending rearwardly from the housing, means defining a receptacle in the rear wall of the broiling chamber, supports for said housing for holding the housing in broiling position with the conduit extending into engagement with the receptacle, a gas jet in said receptacle and having a supply line, means defining a venturi at the jet for drawing in primary air, means defining a primary air passage in the rear wall of the broiling chamber for interconnecting the venturi with the lower portion of the chamber so that clean primary air is drawn from the lower portion of the chamber, a pilot jet having a supply line and mounted upon the rear wall of the broiling chamber for cooperating with a localized region of the burner face when the burner housing is in broiling position in the receptacle, and means for conducting primary air to the pilot jet from the bottom portion of the broiling chamber.

References Cited UNITED STATES PATENTS 3,013,602 12/1961 Heimerl.

3,338,231 8/1967 Lamar.

FOREIGN PATENTS 1,047,723 12/ 1958 Germany.

FREDERICK L. MATTESON, JR., Primary Examiner.

EDWARD G. FAVORS, Assistant Examiner.

US. Cl. X.R. 431-328 Disclaimer 3,422,810.J0hn C". Weiss, Bourbonnais, Ill. BROILER FOR GAS RANGE. Patent dated Jan. 21, 1969. Disclaimer filed July 14, 1969, by the assignee, Geo. D. Roper Corporation. Hereby enters this disclaimer to claims 1, 2, 3, 4 and 5 of said patent.

[Ofiioz'al Gazette November 4, 1.969.] 

